Scientists in Canada have found that a drug called NA-1 results in fewer brain lesions in patients who have undergone surgery to repair brain aneurysms, compared to placebo, and appears to be safe to use. The study has been published online in The Lancet Neurology.

While the primary aim of the double-blind, randomised, phase 2 trial was to assess the safety of the drug in a human population, Michael Hill, University of Calgary’s Hotchkiss Brain Institute, Canada, and colleagues also examined whether injections of NA-1, which disrupts the action of one of the proteins implicated in stroke damage, had any effect on the number and volume of lesions in the brain after patients underwent surgery.

In the study, 185 trial participants received an intravenous infusion of either NA-1 or saline control at the end of the surgical procedure, with 92 participants receiving the study drug, and 93 receiving the control. The participants were given brain MRI scans within three days to determine the extent to which stroke lesions had occurred, and were also followed up after 30 days to assess neurological outcomes.

The researchers found that NA-1 appears to be safe for use in humans, with just two non-serious adverse events (transient low blood pressure) in the study population judged to be related to the drug. The researchers found that use of NA-1 appeared to have some effect in reducing damage to brain tissue in the study population; the researchers recorded significantly fewer lesions in the group of patients who were given the drug compared to the control, although there was no difference between the groups in the volume of lesions recorded.

“Safe drugs to provide tissue neuroprotection – defined as salvage of brain tissue by enhancing its resilience to the restricted blood flow that patients experience during these procedures – is a major unmet need in stroke treatment, and translation from animal studies to humans has been markedly unsuccessful so far,” said Hill, lead author of the study. “Our research, which builds on existing animal studies, suggests that intravenous infusion of NA-1 reduces tissue damage in patients who suffer a small stroke after an operation to repair a brain aneurysm, and further research is now needed to investigate the efficacy of neuroprotection in larger clinical trials.”

In a separate comment, also published in The Lancet Neurology, Markku Kaste, University Central Hospital in Helsinki, Finland, underlines the impact that an effective neuroprotective agent could have, particularly in countries where medical resources are limited, he said: “Because of limited resources in many low-income and middle-income countries, most patients with stroke will not have access to stroke unit care, although such care reduces mortality and chronic institutional care. This holds true, even more, for thrombolysis in ischaemic stroke. Therefore, this underlines the need for safe and effective neuroprotective drugs that can be given at a low service level. However, such drugs should first be assessed in large, well designed and well executed randomised placebo-controlled double-blind clinical trials. Only after such trials will we know whether NA-1 – or one of the other drugs which have shown comparable effects – is the long-awaited holy grail for the treatment of patients with ischaemic stroke. The door is now reopening for new neuroprotection trials in stroke.”